This invention concerns an improvement to the rotor drive motor described in the parent application referenced above.
That application describes a rotor drive motor featuring permanently magnetized fan blades on the rotor which interact with the magnetic fields generated by stator coils arranged at each corner of an enclosing housing.
This greatly reduces the bulk of the fan hub by eliminating the conventional fan motor located at the fan hub, increasing the space available for air flow to substantially improve the performance and efficiency of the fan, particularly useful for installations in constrained spaces.
The fan blades are permanently magnetized in a radial orientation, with each successive blade having magnetic poles oppositely oriented relative to the poles of the adjacent magnetized fan blades. The polarity of the magnetic fields generated by the stator coils are successively reversed by reversing the current applied thereto as each fan blade passes each stator.
By this arrangement, the rotor drive motor stators are thereby located outside the air flow space.
The efficiency of this arrangement depends on the interaction between the stator magnetic field and the magnetic field of the permanently magnetized fan blades.
It is an object of the present invention to improve the output of this rotor drive motor by increasing the torque generated by the interaction of the stator coil and blade magnetic fields.
Another advantage of the improved rotor drive motor using exterior stator coils and magnetized fan blades is that the air flow does not pass through, past, or over the electrical components of the motor and controls.
It is another object of the present invention to provide a fan motor housing arrangement which isolates the air flow from any contact with the electrical components to render the fan suitable for use in an explosive or contaminated atmosphere.